The objective of this research project is to study the structure and function of the three citrate lyase enzymes. One study entails the use of specific stereo isomers of citrate derivatives as possible substrates and inhibitors of the three enzymes. We have studied the four isomers of hydroxycitrate and are at present beginning a study of the fluorocitrate isomers. We will also employ recently developed affinity labels (analogs of acetyl CoA) to determine which amino acid residues are at the active site of citrate synthase and ATP citrate lyase. We will continue our studies on the significance of the phospho group on ATPcitrate lyase. Also we will continue our studies on the control mechanisms for the biosynthesis of this enzyme. For this purpose we shall isolate the message for it and develop analytical techniques for the measure of mRNA. We will continue to explore the mechanisms of biosynthesis of the prosthetic group of bacterial citrate lyase. We are attempting to amplify the production of this enzyme system to make the pathway easier to follow.